Polyphaenolic profiling, antioxidant properties, and inhibition of α-glucosidase of Mesona chinensis benth from Southern China.

• Fifty seven Mesona chinensis Benth phytochemicals were analyzed by UPLC-Q-TOF-MS/MS. • Twenty-three compounds (20 polyphenols; 3 steroids) were found for the first time. • Antioxidant activity showed partly positive relation with MCB polyphenol level. • Nine samples outperformed acarbose; GD-RP showed the best α-glucosidase inhibition. • Farming region affected polyphenol and hypoglycemic levels and antioxidant activity. Mesona chinensis Benth (MCB) polyphenols and polysaccharides were used as functional food supplements; they are added to tea, soup, and black jelly in Southern China. However, information on the polyphenolic constituents of MCB is still scarce. Hence, the polyphenolic profile of MCB was determined using UPLC-Q-TOF-MS/MS, and the antioxidant activities of nine MCB from Southern China were investigated in this study. Fifty seven compounds were identified, namely, 45 polyphenols, 6 terpenoids, and 6 other compounds. Twenty-three phytochemicals were identified in MCB for the first time. Polyphenolic level varied from 127.05 ± 1.54 μg GA/mg DW to 278.36 ± 1.50 μg GA/mg DW and showed a positive relationship with antioxidant activity. Furthermore, MCB produced in Guangdong Raoping exhibited the best antioxidant activity (IC 50 = 0.76 ± 0.06 µg/mL in ABTS, 3.83 ± 0.17 µg/mL in DPPH) and the strongest inhibitory effect on α-glucosidase (IC 50 = 35.05 ± 2.16 µg/mL). Our study enhanced the apperception of polyphenolic constituents and provided a guide for the commercial application of MCB as a potentially rich source of dietary antioxidants and hypoglycemics. [ABSTRACT FROM AUTHOR]